CDC time spikes

Prototype at 2100V, 50/50 Ar/CO2

Tilted detectors

Trigger signals

Scint and coinc logic signals, scope triggered on coinc (magenta)

Same, with TI busy signal (green)

Same, different timebase

Histograms of threshold-crossing bins in central bank of 16 straws, different thresholds (ignore the histo titles)

ADC-value=150 crossing (~approx ped + 5sigma)

3.5sigma crossing (approx ADC value 112 = (55 + 3x16.5))

ADC-value=100 crossing

Histograms of ADC value=100 threshold-crossing bins in individual straws (search started at bin 160)

ADC-value=100 crossing

Same data after more normal analysis (Search forward to find pedestal+5sigma crossing, then backwards to find 4sigma and then 1sigma crossings)

5sigma crossing

4sigma crossing

1sigma crossing

extrapolation to local pedestal crossing

drift time (ns)

2-d histograms of ADC value=mean pedestal+50 (= c. 105 to 110) threshold-crossing bins in each straw vs same for one particular straw Data are plotted for events with non-zero threshold-crossing in both straws. The histos in each image (set of plots) are arranged as in the prototype, these are the images for the bottom row of straws.

straw 9

straw 1

straw 0

straw 8

Noise run (triggered on 20us pulser) ADC=100 crossing bins

ADC=100 crossing bin, triggered on pulser

3.5sigma crossing bin, triggered on pulser

5sigma crossing bin, triggered on pulser

Noise run (triggered on scintillator when prototype was not above/beneath it) ADC=100 crossing bins

ADC=100 crossing bin, random trigger

3.5sigma crossing bin, random trigger

5sigma crossing bin, random trigger

Noise run (triggered on scintillator when prototype was not above/beneath it) ADC=100 crossing bins 2-d histograms of ADC value=100 threshold-crossing bins in each straw vs same for one particular straw Data are plotted for events with non-zero threshold-crossing in both straws. (the histos in each image (set of plots) are arranged as in the prototype but the sets of plots are not).

straw 0

straw 1

straw 2

straw 3

straw 4

straw 5